1. Field of the Invention
The present invention relates to a gas heat pump type air conditioner, in which a compressor for compressing a refrigerant is driven by a gas engine, and which uses waste heat of the gas engine as a heat source for a liquid refrigerant during the heating operation, and an outdoor heat exchanger unit and an outdoor unit, which are suitably used for the gas heat pump type air conditioner.
2. Description of the Related Art
An air conditioner, in which a heat pump is used for cooling and heating a chamber, is provided with a refrigerant circuit comprising an indoor heat exchanger apparatus, a compressor, an outdoor heat exchanger apparatus, an expansion valve, etc. When the refrigerant circulates in the refrigerant circuit and exchanges heat with air in the indoor heat exchanger apparatus and the outdoor heat exchanger apparatus, the chamber is heated or cooled. In general, the refrigerant absorbs heat from the air in the outdoor heat exchanger apparatus during the heating operation. However, not only the outdoor heat exchanger apparatus but also a refrigerant heat apparatus for heating the refrigerant directly is sometimes provided in the refrigerant circuit.
In recent years, an air conditioner has been suggested, which comprises a gas engine, instead of an ordinary motor, as a driving source for the compressor provided in the refrigerant circuit. An air conditioner utilizing a gas engine is called a gas heat pump type air conditioner (abbreviated as xe2x80x9cGHPxe2x80x9d below). The GHP can use gas, which is relatively cheap, as fuel; therefore, the running cost thereof can be reduced, compared with an air conditioner comprising a compressor driven by the ordinary motor (abbreviated as xe2x80x9cEHPxe2x80x9d below).
Moreover, when waste heat of gas at a high temperature discharged from the gas engine during the heating operation is used as the heat source for the refrigerant in the GHP, the heating ability can be improved, and the use efficiency of energy can also be improved. When the temperature of the outdoor air is low, the heating ability of the GHP is 1.2 to 1.5 times as large as the heating ability of the EHP. In addition, when the waste heat of the gas discharged from the gas engine is used in the GHP, the GHP does not require a special device, such as the refrigerant heating device explained above.
Furthermore, the GHP can utilize the engine waste heat to defrost the outdoor heat exchanger apparatus during the heating operation. In general, the EHP defrosts the outdoor heat exchanger apparatus by stopping the heating operation and temporarily performing the cooling operation. That is, when the EHP defrosts, cooled air is introduced into the chamber. Therefore, a person in the chamber feels unpleasant. In contrast, the GHP can utilize the waste heat, and it can continuously perform the heating operation without such a problem which is caused by the EHP.
The GHP has many advantages as explained above; however, it also has the following problems.
FIG. 8 shows a conventional outdoor heat exchanger unit. In FIG. 8, reference number 23 denotes a heat exchanger chamber which is positioned in the upper portion of an outdoor unit, 81 denotes an outdoor fan for introducing outdoor air, and 2 denotes an outdoor heat exchanger unit for exchanging heat between the refrigerant and the outdoor air. The outdoor heat exchanger unit 2 comprises three heat exchangers arranged in series in the flow direction of the outdoor air. Specifically, a radiator 53 is arranged in the center of the outdoor heat exchanger unit 2, and two heat exchangers 31 and 31 sandwich the radiator 53 so as to be positioned upstream and downstream of the flow direction of the outdoor air with respect to the radiator 53. The radiator 53 belongs to a cooling water circuit in which cooling water for the gas engine circulates. As shown in FIG. 8B, the radiator 53 and the two heat exchangers 31 and 31 divide a fin 3. In other words, fins of the radiator 53 and the heat exchangers 31 and 31 are integrated as the fin 3.
In order to improve the heating ability when the temperature of the outdoor air is low, the outdoor heat exchanger unit 2 adopts such a three heat exchanger sandwiched structure. The outdoor heat exchanger unit 2 functions as an evaporator during the heating operation. In the outdoor heat exchanger unit 2, the heat exchangers 31 and 31 can absorb the waste heat radiated from the radiator 53. Therefore, even when the temperature of the outdoor air is low, the outdoor heat exchanger unit 2 can obtain heat required for evaporating the refrigerant from the waste heat of the gas engine.
In contrast, the outdoor heat exchanger unit 2 functions as a condenser during the cooling operation The waste heat of the gas engine, which is radiated from the radiator 53, decreases the efficiency of the refrigerant cycle. In other words, the heat exchangers 31 and 31 as condensers are effected by the waste heat from the radiator 53, and the pressure in the refrigerant cycle increases. Therefore, a large amount of electric power is required to drive the compressor, and the coefficient of performance (COP) of the air conditioner decreases. Moreover, the COP is calculated from the following formula: COP=Qe/L, wherein Qe is the refrigeration capacity, and L is the electric power required for the compressor. Therefore, an outdoor heat exchanger unit has been desired, which can improve the efficiency of the refrigerant cycle without being effected by the engine waste heat during the cooling operation. Moreover, an outdoor heat exchanger unit has also been desired which can improve the efficiency of the refrigerant cycle during the cooling operation and the heating ability by using the gas engine waste heat when the temperature of the outdoor air is low. Furthermore, the development of an outdoor unit comprising the outdoor heat exchanger unit and a GHP comprising the outdoor heat exchanger unit has also been desired.
Therefore, an object of the present invention is to provide: an outdoor heat exchanger unit which is hardly effected by the gas engine waste heat during the cooling operation thereby improving the efficiency of the refrigerant cycle, and which can improve the heating ability by utilizing the gas engine waste heat; an outdoor unit comprising the outdoor heat exchanger unit; and a GHP comprising the outdoor unit.
In order to achieve the object, the present invention provides an outdoor heat exchanger unit for a GHP, in which a compressor for compressing a refrigerant is driven by a gas engine, and which comprises a heat pump for utilizing waste heat of the gas engine to perform a heating and a cooling operations:
wherein the outdoor heat exchanger unit comprises a radiator provided in a cooling water system in which cooling water for the gas engine circulates and an outdoor heat exchanger apparatus provided in a refrigerant circuit in which the refrigerant circulates;
the radiator and the outdoor heat exchanger apparatus are arranged in series in the flow direction of an outdoor air introduced in the outdoor heat exchanger unit;
the radiator is positioned downstream with respect to the outdoor heat exchanger apparatus in the flow direction of an outdoor air introduced in the outdoor heat exchanger unit; and
an interval is between the radiator and the outdoor heat exchanger apparatus.
In the outdoor heat exchanger unit, the interval is between the radiator and the outdoor heat exchanger apparatus; therefore, heat is not conducted between the outdoor heat exchanger apparatus and the radiator. Moreover, the radiator is positioned downstream with respect to the outdoor heat exchanger apparatus in the flow direction of an outdoor air introduced in the outdoor heat exchanger unit. Therefore, the outdoor air heated by the radiator does not pass through the outdoor heat exchanger apparatus. As a result, it is possible to prevent the outdoor heat exchanger apparatus from being effected by adverse effects of the waste heat of the gas engine during the cooling operation. Moreover, the COP can be improved.
In order to achieve the object, the present invention provides an outdoor unit for a GHP, in which a compressor for compressing a refrigerant is driven by a gas engine, and which comprises a heat pump for utilizing waste heat of the gas engine to perform a heating and a cooling operations:
wherein the outdoor unit comprises a gas engine portion comprising the gas engine, a cooling water system comprising a radiator, an exhaust gas system for introducing exhaust gas discharged from the gas engine into outside of the outdoor unit, and a fuel intake system for supplying fuel and air in the gas engine; and a refrigerant circuit comprising the compressor, an outdoor heat exchanger apparatus for exchanging heat between the refrigerant and air introduced therein, and an expansion valve for decompressing and expanding the refrigerant in a liquid state during the cooling operation; and
an outdoor heat exchanger unit is provided in the outdoor unit, in which the radiator and the outdoor heat exchanger apparatus are arranged in series in the flow direction of an outdoor air introduced in the outdoor heat exchanger unit; the radiator is positioned downstream with respect to the outdoor heat exchanger apparatus in the flow direction of an outdoor air introduced in the outdoor heat exchanger unit; and an interval is between the radiator and the outdoor heat exchanger apparatus.
The outdoor unit comprises the outdoor heat exchanger unit in which the interval is between the radiator and the outdoor heat exchanger apparatus; therefore, heat is not conducted between the outdoor heat exchanger apparatus and the radiator. Moreover, the radiator is positioned downstream with respect to the outdoor heat exchanger apparatus in the flow direction of an outdoor air introduced in the outdoor heat exchanger unit. Therefore, the outdoor air heated by the radiator does not pass through the outdoor heat exchanger apparatus. As a result, it is possible to prevent the outdoor heat exchanger apparatus from being effected by adverse effects of the waste heat of the gas engine during the cooling operation. Moreover, the COP can be improved.
In order to achieve the object, the present invention provides a GHP, in which a compressor for compressing a refrigerant is driven by a gas engine, and which comprises a heat pump for utilizing waste heat of the gas engine to perform a heating and a cooling operations:
wherein the GHP comprises an outdoor unit and an indoor unit;
the outdoor unit comprises a gas engine portion comprising the gas engine, a cooling water system comprising a radiator, an exhaust gas system for introducing exhaust gas discharged from the gas engine into outside of the outdoor unit, and a fuel intake system for supplying fuel and air in the gas engine; a refrigerant circuit comprising the compressor, an outdoor heat exchanger apparatus for exchanging heat between the refrigerant and air introduced therein, and an expansion valve for decompressing and expanding the refrigerant in a liquid state during the cooling operation;
an outdoor heat exchanger unit is provided in the outdoor unit, in which the radiator and the outdoor heat exchanger apparatus are arranged in series in the flow direction of an outdoor air introduced in the outdoor heat exchanger unit; the radiator is positioned downstream with respect to the outdoor heat exchanger apparatus in the flow direction of an outdoor air introduced in the outdoor heat exchanger unit; and an interval is between the radiator and the outdoor heat exchanger apparatus; and
an indoor unit comprises a fan for drawing indoor air and blowing out it from an opening, and an indoor heat exchanger apparatus for exchanging heat between the refrigerant supplied from the outdoor unit and the indoor air drawn by the fan.
The GHP comprises the outdoor unit provided with the outdoor heat exchanger unit in which the interval is between the radiator and the outdoor heat exchanger apparatus; therefore, heat is not conducted between the outdoor heat exchanger apparatus and the radiator. Moreover, the radiator is positioned downstream with respect to the outdoor heat exchanger apparatus in the flow direction of an outdoor air introduced in the outdoor heat exchanger unit. Therefore, the outdoor air heated by the radiator does not pass through the outdoor heat exchanger apparatus. As a result, it is possible to prevent the outdoor heat exchanger apparatus from being effected by adverse effects of the waste heat of the gas engine during the cooling operation. Moreover, the COP can be improved.
In the GHP, it is preferable that it further comprises a fan for introducing outdoor air into outdoor heat exchanger unit; the fan rotates in a normal mode so as to introduce outdoor air through the outdoor heat exchanger apparatus and radiator in turn during the cooling operation; and the fan rotates in a reverse mode so as to introduce outdoor air through the radiator and the outdoor heat exchanger apparatus in turn during the heating operation.
The GHP is not effected by adverse effects of the waste heat of the gas engine during the cooling operation. In contrast, the heating ability can be improved by utilizing the waste heat of the gas engine during the heating operation.
In the GHP, it is possible that it further comprises a water heat exchanger apparatus for absorbing waste heat of the gas engine from cooling water circulating in the cooling water system and evaporating the refrigerant; and a constant pressure expansion valve is used as the expansion valve.
According to the GHP, a pressure decrease in the circulating refrigerant can be prevented, and frost of the outdoor heat exchanger apparatus can be prevented. Therefore, when the efficiency of the gas engine is improved, and thereby the waste heat of the gas engine decreases; a decrease in the heating ability can be prevented.
In the GHP, it is preferable that the outdoor heat exchanger apparatus comprises at least three heat exchangers arranged in series in the flow direction of outdoor air introduced into an outdoor heat exchanger unit; at least one heat exchanger which is not arranged at both sides of the outdoor heat exchanger apparatus is a warm water heat exchanger belongs to the cooling water system; and the cooling water system further comprises a valve for selectively introducing cooling water of the gas engine into the warm water heat exchanger.
According to the GHP, the valve is closed during the cooling operation, and thereby the cooling water for the gas engine does not pass through the warm water heat exchanger. Therefore, the outdoor heat exchanger apparatus is not effected by adverse effects of the waste heat In contrast, during the heating operation, the valve is opened, and thereby the cooling water for the gas engine passes through the radiator and the warm water heat exchanger. Therefore, the refrigerant can absorb heat sufficient for evaporation from the waste heat of the cooling water for the gas engine.
Moreover, in the GHP, it is more preferable that the valve is operated so as to introduce the cooling water into the warm water heat exchanger depending on conditions under which frost is generated in the outdoor heat exchanger apparatus during the heating operation and temperature of outdoor air is low.
According to the GHP, it is possible to prevent the outdoor heat exchanger apparatus from frosting. Therefore, a decrease in the heating ability can be prevented.